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Imprint
Detection of Shiga Toxin-producing E. coli (STEC) carrying the Shiga toxin-variant Stx2d in isolates from livestock, food and the environment. Studies on their virulence markers and their spectrum of serotypes
Project
Project code: BfR-BIOS-08-1322-579
Contract period: 01.03.2014
- 31.12.2015
Purpose of research: Applied research
There are substantial differences with respect to their virulence for humans between the different Shiga toxin 2 (Stx2)-subtypes. A high virulence is attributed to the subtypes Stx2a, Stx2c und Stx2d. The Shiga Toxin-variant Stx2d differs from the other presently known Shiga Toxins in that its cytotoxicity can be activated, viz. increased 10- to 1,000-fold, by incubating with mucosa cells from the intestine of mice and humans. The presence of this activatable Shiga Toxin in Shiga Toxin-producing E. coli (STEC) strains infecting humans and its activation by human intestinal mucus during infection results in increased virulence of such strains for humans. Severe clinical outcome including haemolytic uremic syndrome is the consequence. Of the 1,200 Stx2-positive strains isolated from livestock, food, the environment and human feces and investigated in this research project, 311 (26%) proved stx2d-positive. 97% of these strains did not carry the intimin-encoding eae-gene. The major virulence traits and the spectrum of serotypes of these strains were characterized. A number of real-time PCR procedures was developed to screen the strains for additional potential virulence and adherence factors including toxins and serine proteases which could be pathogenetically significant. These data are necessary in order to get to assess the importance of stx2d-positive strains as cause of human STEC infections.
Section overview
Subjects
- Biotechnology
- Food microbiology
- Toxicology
